Helicopter

ABSTRACT

A helicopter ( 2 ) comprising a body portion ( 4 ), a plurality of rotor blades ( 6 ) which are mounted for rotation with respect to the body portion ( 4 ), and a fan ( 8 ) which is mounted for rotation in an opposite direction to the direction of rotation of the rotors ( 6 ), the rotor blades ( 6 ) being such that they are spaced apart in a vertical direction, and the fan ( 8 ) being such that when it rotates it generates a torque which acts to counteract at least a part of the torque generated by the rotor blades ( 6 ) when they rotate.

This invention relates to a helicopter.

Known helicopters have large rotor spans. These rotor spans may exceed twenty five feet. This means that the helicopters require relatively large spaces in which to land. The known helicopters are also expensive to manufacture, and also expensive to maintain and run due to high continuous engine speeds. The above problems are particularly acute for helicopters for private use, which helicopters are often purchased as home-build helicopters for being constructed by private persons.

It is an aim of the present invention to reduce the above mentioned problems.

Accordingly, in one non-limiting embodiment of the present invention there is provided a helicopter comprising a body portion, a plurality of rotors which are mounted for rotation with respect to the body portion, and a fan which is mounted for rotation in an opposite direction to the direction of rotation of the rotors, the rotors being such that they are spaced apart in a vertical direction, and the fan being such that when it rotates it generates a torque which acts to counteract at least a part of the torque generated by the rotors when they rotate.

With the helicopter of the present invention, the rotor span is able to be drastically reduced due to the use of the plurality of rotors which are spaced apart in a vertical direction. Thus the required helicopter lift is able to be obtained with shorter rotors than would normally be the case with rotors extending only in a horizontal direction. With the helicopter of the present invention, the engine is able to run at a much lower speed, for example less than half of the speed of a conventional known helicopter. This enables the helicopter of the present invention to have low maintenance costs and low running costs. The helicopter may also be constructed so that it can be produced at a significantly lower cost than known helicopters, for example one third of the cost of existing kits for producing home-build helicopters of a comparable size.

The helicopter may be one in which the rotors are in a plurality of vertical sets. There may be four-eight of the vertical sets. Preferably there are six of the vertical sets.

The helicopter may be one in which the rotors in each vertical set are mounted on a spar, and in which the spar rotates to cause rotation of the rotors mounted on the spar.

Preferably, the spars for each vertical set of rotors curve inwardly from a base part of the body portion towards a top part of the body portion. Also preferably, the spars are connected together at the top part of the body portion.

The helicopter may include control rods for the rotors, the control rods being positioned inside the spars. Control means other than control rods for the rotors may be employed. The control means, for example the control rods, may be positioned outside the spars if desired.

There may be four-eight rotors in each vertical set. Preferably there are six rotors in each vertical set.

Preferably, the helicopter is one in which the rotors in each vertical set vary in length, and in which the rotors in each vertical set progressively increase in length, with the shortest rotor being adjacent the base part of the body portion.

The fan will usually have a plurality of blades.

Preferably, the fan generates a torque which counteracts substantially all of the torque generated by the rotors when they rotate. In this case, the fan may advantageously have the same number of blades as there are rotors.

The helicopter may include drive means for driving the rotors and the fan. The drive means may drive a vertically extending shaft. The shaft may connect to and drive the spars, when the spars are present.

The helicopter may operate such that the drive means is coupled to the spars by a swash plate assembly. The purpose of the swash plate assembly is to enable the pitch of the rotors to be varied.

Under the direction of the collective control from the swash plate, the angle of all the rotors are able to be changed simultaneously, thus increasing or decreasing the lift that the rotors provide.

Under the direction of the cyclic control from the swash plate, the swash plate assembly is able to change the angle of the rotors on a group of spars, thus allowing the pitch of the helicopter to be altered. This alteration of pitch enables a full 360° movement forward-backward-left-right. The spars may be retained at the base part of the body portion in a ring that runs in circumferential bearings attached to the base part.

The fan may be coupled to the drive means by six spokes set at 60° intervals from a central drive hub beneath the base part. The fan blades have inner edges which may be retained in a ring that runs in circumferential bearings attached to the base part. The control means is carried within spokes to the blades of the fan. At the hub, a similar swash plate assembly may be provided in order to enable the pitch of the blades to be altered.

The swash plate assembly preferably consists of two plates, one fixed and the other rotating. The rotating plate rotates with the drive shaft and the rotors, due to connecting links between the rotating plate and the drive shaft.

Pitch control rods may enable the rotating plate to change the pitch of the rotors.

The angle of the fixed swash plate may be varied by another set of control rods attached to the fixed plate. The control rods of the fixed plate are controlled by the pilot's controls. There will usually be bearings employed between the two plates. Raising or lowering the fixed plate alters the collective pitch of the rotors. By tilting the fixed plate, the cyclic pitch is altered.

The helicopter may include seating in the body portion. Preferably, the seating is for four persons. This compares favourably with the seating in present home-build helicopters which are usually only capable of carrying a maximum of two persons.

The body portion may have transparent walls. Persons in the helicopter are thus able to be given a good 360° view. Although the helicopter of the present invention is able to operate such that the drive means operates at a much lower speed compared with the drive means in known helicopters, the reduced speed of the rotating rotors and the rotating spars does not adversely impede visibility of the operator of the aircraft.

The helicopter of the present invention may employ conventional helicopter controls. Cyclic and collective control may be achieved by the control rods or other control means. The helicopter of the present invention will usually employ conventional throttle controls.

The helicopter may have conventional skids. These skids may be employed on four angled sprung legs. Alternatively, the helicopter may have three castored double wheels set at 120° radially beneath the helicopter. The castored double wheels may be helpful in manoeuvering the helicopter when it is on the ground.

An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawing.

Referring to the drawing, there is shown a helicopter 2 comprising a body portion 4, and a plurality of rotors 6 which are mounted for rotation with respect to the body portion 4. A fan 8 is mounted for rotation in an opposite direction to the direction of rotation of the rotor 6. The rotors 6 are such that they are spaced apart in a vertical direction. The fan 8 is such that when it rotates, it generates a torque which acts to counteract at least a part of the torque generated by the rotors 6 when they rotate.

As can be seen from the drawing, the rotors 6 are in a plurality of vertical sets. There are six rotors 6 in each vertical set.

The rotors 6 in each vertical set are mounted on a spar 10. Each spar 10 rotates to cause rotation of the rotors 6 mounted on the spar 10. The spar 10 for each set of rotors 6 curves inwardly from a base part 12 of the body portion 4 towards a top part 14 of the body portion 4.

The spars 10 are connected together at the top part 14 of the body portion 4.

The helicopter includes control rods (not shown) for the rotors 6. The control rods are positioned inside the spars 10.

As can be seen from the drawing, the six rotors 6 in each vertical set of the rotors are such that they each vary in length. More specifically, the rotors 6 in each vertical set progressively increase in length, with the shortest rotor 6 being adjacent the base part 12 of the body portion 4. Thus the longest rotor 6 is adjacent the top part 14 of the body portion 4.

The fan 8 has a plurality of blades 16. The fan 8 is such that it generates a torque which acts to counteract substantially all of the torque generated by the rotors 6 when they rotate. In order to do this, the fan 8 is provided with the same number of blades 16 as there are rotors 6. Other fan designs may be used to ensure that the fan 8 generates a torque which counteracts substantially all of the torque generated by the rotors 6 when they rotate. The blades of the fan may also act to give some lift to the helicopter 2, this lift being supplementary to the main lift for the helicopter 2 which is caused by the rotors 6.

The helicopter 2 includes drive means 18 for driving the rotors 6 and the fan 8. The drive means 18 drives a vertically extending rotating shaft 19. This drive shaft 19 may extend from the drive means 18 vertically to the top part 14 of the body portion 4, where the drive shaft 19 will make driving contact with the top parts of the spars 10.

The helicopter includes seating in the form of seats 20 in the body portion 4. There are preferably seats for four persons.

The body portion 4 has transparent walls, in order to give persons sitting on the seats 20 good 360° visibility.

The helicopter 2 is mainly intended as a home-build helicopter and it may be sold in home-build kit form. The cost of the helicopter, 2 may be approximately one third of the cost of an existing kit for building a generally comparable known helicopter. The helicopter 2 may have low maintenance costs because the drive means 18 is able to run at a much lower speed than the drive means in conventional helicopters. Thus, for example, the drive means may have a motor which runs at less than half of the speed in a conventional helicopter. The low running speed of the drive means 18 gives low maintenance costs and low running costs.

The rotors 6 may be such that there are six rotors which are five feet in length, six rotors which are four feet in length, six rotors which are three feet in length, six rotors which are two feet in length, six rotors which are one foot in length, and six rotors which are 0.5 feet in length. This give a total rotor length of 93 feet. In spite of this, the helicopter 2 only has an overall diameter of twelve feet. Thus the helicopter 2 is able to land and operate in relatively small spaces, which is a big advantage for home-build helicopters which are used privately and which often land and take off in gardens or around persons' homes. By way of comparison, a known helicopter might have a wing span of more than twenty-five feet. The helicopter 2 is thus able to be significantly smaller in size. The helicopter 2 is also able to be built at a significantly lower cost than a known comparable helicopter. In addition, the majority of known home-build helicopters are only able to carry two persons, whereas the helicopter 2 can carry four persons if desired. Due to the very large rotor area afforded by the rotors 6, the drive means 18 is able to operate at the lower speed, and thereby provide the further advantages of low maintenance costs and low running costs.

Although not shown in the drawing, the helicopter 2 has three castored double wheels set at 120° radially beneath the helicopter 2.

It is to be appreciated that the embodiment of the invention described above with reference to the accompanying drawing has been given by way of example only and that modifications may be effected. Thus, for example, more or less rotors than six rotors may be employed on each spar, and more or less spars may be employed than six spars. The helicopter 2 may be increased in size to act as a passenger carrier, in which case the seating will then be for more than four persons. 

1. A helicopter comprising a body portion, a plurality of rotors which are mounted for rotation with respect to the body portion, and a fan which is mounted for rotation in an opposite direction to the direction of rotation of the rotors, the rotors being such that they are spaced apart in a vertical direction, and the fan being such that when it rotates it generates a torque which acts to counteract at least a part of the torque generated by the rotors when they rotate.
 2. A helicopter according to claim 1 in which the rotors are in a plurality of vertical sets.
 3. A helicopter according to claim 2 in which there are four-eight of the vertical sets.
 4. A helicopter according to claim 3 in which there are six of the vertical sets.
 5. A helicopter according to claim 2 in which the rotors in each vertical set are mounted on the spar, and in which the spar rotates to cause rotation of the rotors mounted on the spar.
 6. A helicopter according to claim 5 in which the spars for each set of rotors curve inwardly from a base part of the body portion towards a top part of the body portion.
 7. A helicopter according to claim 6 in which the spars are connected together at the top part of the body portion.
 8. A helicopter according to claim 5 and including control rods for the rotors, the control rods being positioned inside the spars.
 9. A helicopter according to claim 2 in which there are four-eight rotors in each vertical set.
 10. A helicopter according to claim 9 in which there are six rotors in each vertical set.
 11. A helicopter according to claim 2 in which the rotors in each vertical set vary in length, and in which the rotors in each vertical set progressively increase in length, with the shortest rotor being adjacent to a base part of the body portion.
 12. A helicopter according to claim 1 in which the fan has a plurality of blades.
 13. A helicopter according to claim 1 in which the fan generates a torque which acts to counteract substantially all of the torque generated by the rotors when they rotate.
 14. A helicopter according to claim 12 in which the fan has the same number of blades as there are rotors.
 15. A helicopter according to claim 1 and including drive means for driving the rotors and the fan.
 16. A helicopter according to claim 14 in which the drive means drives a vertically extending rotating shaft.
 17. A helicopter according to claim 1 and including seating in the body portion.
 18. A helicopter according to claim 17 in which the seating is for four persons.
 19. A helicopter according to claim 1 in which the body portion has transparent walls. 